Controlair Type Transducer
Marsh Bellofram Type Transducer
Flowserve Type Transducer
EPC Type TransducerTT7800 Electro Pneumatic Converter
The TT7800 is the terminal block build of the T7800 family, available in both standard and extended range. As a converter it is the unit to specify where the control signal is a voltage, 0-10 VDC or 1-9 VDC, and the field cable is landed on screws inside the instrument.
What This Model Is
The TT7800 Series Electro Pneumatic Converter provides maximum versatility for precision applications. The three-wire voltage input takes 7.2 to 30 VDC at less than 3 mA with a 10 kilohm signal impedance, so a controller voltage output drives it without an intermediate converter. The terminal block termination keeps the wiring inside the enclosure.
How It Works
The Model T7800 Series converts a DC input signal to a linear proportional pneumatic output. It includes the Primary Converting Section and the pneumatic Relay Section. The piezoelectric ceramic actuator in the Primary Converting Section functions as a flapper. The flapper and nozzle work together to control the signal pressure. That signal pressure acts on the upper control diaphragm in the Relay Section, and the lower control diaphragm senses the output pressure. In extended range units an additional relay section amplifies the output pressure.
TT7800 Electro Pneumatic Converter On Our Benches
Studio and workshop photographs of the units as built, not renderings.
What You Get From This Model
Voltage input without a converter stage
0-10 VDC and 1-9 VDC are native inputs, with a published 10 kilohm signal impedance for the three-wire voltage connection.
Terminal block inside the enclosure
Field cable is glanded and landed on screws, so there is no external plug to protect.
Standard and extended range
The TT7800 is catalogued in both, so the same termination covers a small actuator and a large one.
Precision figures unchanged
0.25% full scale guaranteed accuracy, 0.1% hysteresis and repeatability, 0.02% deadband, and no measurable position or supply pressure effect.
Where It Is Used
- Voltage-signalled loops driving pneumatic final elements
- Cabled field instruments landed on terminals
- Split range control of two or more functions from one signal
- Precision pressure control indoors and outdoors
- Replacement of a terminal-block transducer in an existing installation
Who Orders It
- Plants that signal in volts rather than milliamps
- Instrument technicians who prefer a terminal block to a plug
- Engineers specifying both standard and extended range on one model
- Automation builders wiring inside the instrument enclosure
What This Model Fixes
A voltage loop has been forced through a current instrument
The three-wire voltage input removes the intermediate stage and the failure point that comes with it.
A plug-in connector is exposed on a wet installation
The terminal block build keeps the termination inside a NEMA 4X, IP65 enclosure.
Two final elements have to share one signal
Split range operation lets a common signal source control two or more functions.
The loop needs different ranges on the same termination
The TT7800 is catalogued in standard and extended range.
Features And Specifications
Every figure below is transcribed from the datasheet EAA publishes for this series. Anything not published is not listed.
- Terminal block electrical connection
- Standard range and extended range builds
- Three-wire voltage input, 10 kilohm signal impedance
- Field reversible output, inversely proportional to the input signal
- RFI and EMI protection
- Internal electronic feedback with a solid state controlled piezoelectric actuator
- Damping adjustment for optimum tuning response
- Split range operation from a common signal source
- Compact size for restricted spaces
- NEMA 4X, Type 4 enclosure, IP65 rated for indoor and outdoor installation
- Canadian Registration Numbers (CRN) certification for all territories and provinces
| Set point | 3 psig [0.2 BAR] (20 kPa) | 9 psig [0.6 BAR] (60 kPa) | 15 psig [1.0 BAR] (100 kPa) | 30 psig [2.0 BAR] (200 kPa) |
|---|---|---|---|---|
| Maximum air consumption, all ranges | 3.5 SCFH (0.10 m3/HR) | 7.0 SCFH (0.20 m3/HR) | 9.5 SCFH (0.27 m3/HR) | 13.5 SCFH (0.38 m3/HR) |
| Range | Low | Middle | High |
|---|---|---|---|
| Output range | 3-15 psig [0.2-1.0 BAR] (20-100 kPa) | 3-27 psig [0.2-1.8 BAR] (20-180 kPa) | 6-30 psig [0.4-2.0 BAR] (40-200 kPa) |
| Supply pressure | 20-120 psig [1.5-8.0 BAR] (150-800 kPa) | 32-120 psig [2.2-8.0 BAR] (220-800 kPa) | 35-120 psig [2.4-8.0 BAR] (240-800 kPa) |
| Minimum span | 5 psig [0.35 BAR] (35 kPa) | 10 psig [0.7 BAR] (70 kPa) | 10 psig [0.7 BAR] (70 kPa) |
| Parameter | Value |
|---|---|
| Input range | 4-20 mA DC, 0-10 VDC, 1-9 VDC |
| Flow rate | 2.5 SCFM (4.25 m3/HR) at 25 psig [1.7 BAR] (170 kPa) supply and 9 psig [0.6 BAR] (60 kPa) output, or 9.0 SCFM (15.3 m3/HR) at 120 psig [8.0 BAR] (800 kPa) supply and 9 psig output |
| Accuracy (ISA S51.1) | 0.25% full scale guaranteed, 0.15% full scale typical |
| Hysteresis (ISA S51.1) | 0.1% full scale |
| Deadband | 0.02% full scale |
| Repeatability (ISA S51.1) | 0.1% full scale |
| Frequency response | -3 dB at 5 Hz per ISA S26.4.3.1 load configuration A |
| Operating temperature | -40 F to +160 F (-40 C to +71.2 C) |
| Storage temperature | -40 F to +180 F (-40 C to +82.2 C) |
| Required operating voltage | Two-wire current input 7.2 VDC at 20 mA (4-20 mA signal); three-wire voltage input 7.2-30 VDC, less than 3 mA |
| Signal impedance | Three-wire voltage input 10 kilohms |
| Span and zero adjustment | Screwdriver adjustments located on the front of the unit |
| Position effect | No measurable effect |
| Supply pressure effect | No measurable effect |
| Temperature effect | +0.5% +0.04% per F temperature change of span, typical |
| Vibration effect | Less than +/-1% of span at 5-15 Hz with 0.8 inch constant displacement and 15-500 Hz at 10 G |
| Reverse polarity protection | No damage from reversal of normal supply current (4-20 mA) or from misapplication of up to 60 mA |
| RFI / EMI effect | Less than 0.5% of span at 30 V/m class 3 band ABC (20-1000 MHz) per SAMA PMC 33.1 1978, and less than 0.5% of span at 10 V/m to 2 GHz per EN 61000-4-3:1998 +A1, EMC Directive 89/336/EEC, European norm EN 61326 |
| Component | Material |
|---|---|
| Body and housing | Chromate treated aluminium |
| Orifice | Nickel plated brass and sapphire |
| Trim | Stainless steel, brass and zinc plated steel |
| Elastomers | Nitrile |
| Model | Electrical connection and range |
|---|---|
| TT7800 | Terminal block. Available in standard range and extended range. |
| TA7800 | 1/2 inch NPT conduit fitting with pigtail. Available in extended range. |
| TD7800 | DIN 43650 connection. Available in standard range and extended range. |
| TR7800 | For use with the TR manifold rack kit. Same as the TT7800 except that the terminal block is located on the rear. Available in standard and extended range. |
Selecting Installing And Calibrating
- Check the supply voltage for the input typeTwo-wire current input needs 7.2 VDC at 20 mA. Three-wire voltage input needs 7.2 to 30 VDC at less than 3 mA.
- Land the cable and resealTerminate inside the enclosure and refit the cover so the NEMA 4X and IP65 rating is kept.
- Set the split range points if usedWhere two elements share a signal, set each unit's zero and span so the two ranges meet without overlap.
- Tune damping after calibrationCalibrate zero and span first, then use the damping adjustment for the response the loop needs.
How It Compares With The Alternatives
TT7800 is the terminal block build; TD7800 uses a DIN 43650 plug, TA7800 a conduit pigtail and TR7800 a rear terminal block for the manifold rack kit. The TR7800 is otherwise the same unit as the TT7800. Pick on the termination the installation standard calls for.
| Model | Distinguishing specification | Best suited to |
|---|---|---|
| TT7800 Electro Pneumatic Converter | Terminal block, standard and extended range | Cabled installations, voltage signalling |
| TA7800 Electro Pneumatic Transducer | Conduit fitting with pigtail | Conduit-wired field installations |
| TD7800 Electro Pneumatic Converter | DIN 43650 connection | Plug-in terminations |
Related cases
- No OEM case published for this model yet.
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View specifications →Questions About The TT7800 Electro Pneumatic Converter
What does the second T in TT7800 mean
It is the electrical connection: a terminal block. The TR7800 is the same unit with the terminal block on the rear for the TR manifold rack kit.
Which voltage inputs does it accept
0-10 VDC and 1-9 VDC on a three-wire connection, with a 10 kilohm signal impedance and a 7.2 to 30 VDC supply at less than 3 mA. 4-20 mA DC is also available.
Is it available in extended range
Yes. The TT7800 is catalogued in both standard range and extended range.
What output ranges are available
3-15 psig (0.2-1.0 BAR, 20-100 kPa), 3-27 psig (0.2-1.8 BAR, 20-180 kPa) and 6-30 psig (0.4-2.0 BAR, 40-200 kPa) in the standard range.
How much air does it consume
3.5 SCFH at a 3 psig set point, rising to 13.5 SCFH at a 30 psig set point.
Request A Price For The TT7800
Tell us the input signal, the output range and the electrical termination, and the quotation comes back against the published part number.